The present invention relates to the positioning and drilling of holes for the fixation of surgical implants and, more particularly, to an optical system and a method to assist a surgeon, and more particularly a dental implantologist or an orthopedic surgeon, in drilling at a predetermined location, distance and angulations relative to references.
A diverse variety of surgical and dental prostheses and appliances are affixed, permanently or temporarily, to the bone of a patient using bone screws, implants, nails, plates, pins or other fasteners. A major problem encountered by the surgeon is the drilling of holes for securing such appliances in the bone in the correct location, properly spaced from one another, and correctly oriented in space relative to one another.
Failure to place and align the holes properly can lead to many complications including improper fitting of the appliance, as well as damage to the bone and associated vascular and nervous tissues. When a load is placed on an appliance secured to holes that have been improperly placed and oriented, strains are placed on the bone that can damage the bone, lead to failure of the implant or secondary infection.
At the present time, in most cases such holes are typically drilled free-hand. In some cases the initial drilling of the holes is guided by template. In common orthopedic practice, when holes are drilled close to one another a mechanical guide may be used, but over long distances of bone (such as encountered in the limbs), placement of holes distant from one another is often guided by x-ray. This generally does not achieve precise localization and orientation, and especially angulation, and particularly not in three-dimensions since the x-ray provides only a two dimensional image. In addition, usage of x-rays involves the hazards of excessive and unnecessary radiation exposure to the patient as well as the surgeon and operating theater personnel.
Dental implants have become a standard dental procedure for the replacement of missing teeth. They do not use part of the original tooth as a foundation for the tooth replacement, but rather the drilling of holes directly into the jaw bone. In current practice, metal implants for artificial teeth are screwed into holes drilled into the human jaw. The artificial teeth have holes made in respect to the implanted screw heads. When mounted, the teeth are pushed over and screwed or cemented to posts that are screwed and fixed into the implants.
It is well understood, that for the teeth to slide properly into place, and for a snug fit with the implant posts, it is important to have parallel implants. This means that it is important to drill and enlarge the holes in the jaw parallel to one another, and located according to a predetermined plan. Today, the commonly used practice cannot assure the geometrical positioning of these holes when drilled and enlarged to the final size.
Attempts have been made to use devices to permit improved positioning of drilled holes for implants and other surgical appliances. U.S. Pat. No. 5,954,769 to Rosnlicht, U.S. Pat. No. 5,915,962 to Rosenlicht, U.S. Pat. No. 5,967,777 Klein, and U.S. Pat. No. 6,062,856 to Sussman disclose devices that are examples of attempted mechanical solutions to the difficulties encountered in placement and spacing of holes for implants. All of these, however, suffer from significant limitations. None of them achieves a sufficient and optimal degree of accuracy and precision of placement and orientation. The placement of orientation, spacing and angulation they allow is not precise in three dimensions. Because the devices rely on mechanical methodologies there is a limit to the distance over which they can be used and a limit to the distance over which they can be used with accuracy without increasing significantly the size of the guides. Accuracy is further diminished when these devices are used on curved or arching surfaces. Because they are mechanical devices they are bulky and inconvenient. Further, they are slow to use as they need to be screwed and fastened into place and then unscrewed. The mechanical guides and templates must be removed after partial drilling of the initial hole: they can only be maintained in place to allow drilling to the depth at which the drill head contacts the template and do not permit drilling to the full extent of the drill bit.
There is thus a widely recognized need for, and it would be highly advantageous to have, a system and a method to assist a surgeon, and more particularly a dental implantologist or an orthopedic surgeon, in drilling at a predetermined location, distance and angulations relative to references devoid of the above limitations.
According to the present invention there is provided a system and a method for the positioning and drilling of holes for the fixation of surgical implants and, more particularly, to an optical system and a method to assist a surgeon, and more particularly a dental implantologist or an orthopedic surgeon, in drilling at a predetermined location, distance and angulations relative to references.
According to one aspect of the present invention there is provided a system for positioning a drill for drilling a hole in a bone at a predetermined distance from, and in a predetermined orientation in respect to, a reference hole, the drill having a drill bit with a central axis, the system including: (a) a reference insert, configured to be inserted into the reference hole, and adapted to establish a reference guideline, the reference guideline being of the predetermined orientation; and, (b) an alignment mechanism, configured to be attached to the drill, the alignment mechanism adapted to be adjusted to the predetermined distance from and parallel to the central axis of the drill bit, the alignment mechanism including an optical device for colinearly aligning an alignment axis of the alignment mechanism with the reference guideline.
According to another aspect of the present invention there is provided a method for positioning a drill for drilling a subsequent hole in a bone at a predetermined distance from, and in a predetermined orientation in respect to, a reference hole, the drill having a drill bit with a central axis, the method comprising the steps of: (a) inserting a reference insert into the reference hole, the reference insert being adapted to establish a reference guideline, the reference guideline being of the predetermined orientation; (b) providing an alignment mechanism, attached to the drill, the alignment mechanism adapted to be fixed at the predetermined distance from and parallel to the central axis of the drill bit, the alignment mechanism including an optical device for colinearly aligning an alignment axis of the alignment mechanism with the reference guideline; (c) fixing the alignment mechanism at the predetermined distance; and, (d) aligning the alignment axis of the optical device of the alignment mechanism with the reference guideline, thereby positioning the drill at the predetermined distance from and in the predetermined orientation in respect to the reference hole.
According to further features in preferred embodiments of the invention described below, the reference insert has a central longitudinal axis and an upper surface, the upper surface being perpendicular to the central longitudinal axis, and the upper surface serving as a reference standard for the orientation of the hole in the bone.
According to still further features in the described preferred embodiments the reference insert has a central longitudinal axis and an upper surface, the upper surface being inclined at an obtuse angle relative to the central longitudinal axis, and the upper surface serving as a reference standard for the orientation of the hole in the bone.
According to still further features in the described preferred embodiments the reference insert is of a generally cylindrical shape.
According to still further features in the described preferred embodiments the reference insert has an upper surface, and the upper surface is lustrous.
According to still further features in the described preferred embodiments the reference insert is adapted for insertion into a previously drilled hole in bone.
According to still further features in the described preferred embodiments the reference insert is adapted for insertion into a prefabricated hole in a surgical fastener.
According to still further features in the described preferred embodiments the surgical fastener is a dental implant.
According to still further features in the described preferred embodiments the alignment mechanism is attached to the drill by an adjustable mechanism for adjusting the distance between the drill bit and the alignment mechanism.
According to still further features in the described preferred embodiments the alignment mechanism is attached to the drill by a slider for adjusting the distance between the drill bit and the alignment mechanism.
According to still further features in the described preferred embodiments the alignment mechanism is fixed at the predetermined distance from and parallel to the central axis of the drill bit by a tightening mechanism.
According to still further features in the described preferred embodiments a light source is connected to the reference insert, the light source producing a light beam for establishing the reference guideline.
According to still further features in the described preferred embodiments the light source is selected from the group consisting of a light emitting diode, a laser, and a fiber optic strand connected to a lamp.
According to still further features in the described preferred embodiments the light source includes a collimator for limiting a diameter and a dispersion angle of the light beam.
According to still further features in the described preferred embodiments the optical device includes at least two targets, the targets establishing the alignment axis of the alignment mechanism.
According to still further features in the described preferred embodiments the optical device includes a target support for maintaining in position the at least two targets.
According to still further features in the described preferred embodiments a first target of the at least two targets is an aperture on a first surface of the target support, the first surface being perpendicular to the alignment axis.
According to still further features in the described preferred embodiments a shape of the aperture is selected from the group consisting of a circle, a slit, and a cross.
According to still further features in the described preferred embodiments a shape of the aperture is filled with a filter, the filter having imprinted thereon an indicator marking.
According to still further features in the described preferred embodiments a second target of the at least two targets is placed on a second surface of the target support, the second surface being interior of the target support and parallel to and opposite to the first surface.
According to still further features in the described preferred embodiments the second target is an indicator marking.
According to still further features in the described preferred embodiments the target support is a cylindrical tube.
According to still further features in the described preferred embodiments the target support is a prism, the prism having at least three surfaces.
According to still further features in the described preferred embodiments, a first target of the at least two targets is placed on a first plane of the prism, the first plane being parallel to a first surface of the prism; a second target of the at least two targets is placed on a second plane of the prism, the second plane being parallel to a second surface of the prism; and, a third surface of the prism is a mirror.
According to still further features in the described preferred embodiments the reference guideline and the alignment axis are colinearly aligned by the light beam illuminating all of the at least two targets.
According to still further features in the described preferred embodiments the optical device includes a light source, the light source producing a light beam.
According to still further features in the described preferred embodiments the light source is selected from the group consisting of a light emitting diode, a laser, and a fiber optic strand connected to a lamp.
According to still further features in the described preferred embodiments the light source includes a collimator for limiting a diameter and a dispersion angle of the light beam.
According to still further features in the described preferred embodiments the optical device further includes a target, the target being fixed in position in the optical device and adapted to establish the alignment axis.
According to still further features in the described preferred embodiments the reference insert includes a mirror on the reference insert, the mirror being adapted to establish the reference guideline.
According to still further features in the described preferred embodiments the mirror is on an upper surface of the reference insert.
According to still further features in the described preferred embodiments the reference insert is hollow, forming a cavity, and the mirror is placed within the cavity.
According to still further features in the described preferred embodiments the light source and the target are fixed in position in the optical device such that the alignment axis is colinearly aligned with the reference guideline when the light beam incident on the mirror produces a reflected beam, and the reflected beam is colinear with the alignment axis of the target.
According to still further features in the described preferred embodiments the optical device includes a prism, wherethrough the light beam and the reflected beam pass, the prism having at least three faces.
According to still further features in the described preferred embodiments the faces are both reflective and transparent to light.
According to still further features in the described preferred embodiments the light beam first penetrates a first face of the at least three faces, such that the light beam is bent so as to pass through a second face of the at least three faces and the light beam produces a first image on a third face of the at least three faces; the second face is placeable opposite the reference insert, such that the beam is incident on the reference insert, and the reflected beam passes through the second face so as to be reflected by the first face to produce a second image on the third face; and, the first image and the second image are coincident such that only a single representation of the light beam is produced on a plane parallel to the third face when the alignment axis and the reference guideline are colinearly aligned.
According to still further features in the described preferred embodiments the prism has adjustable angles.
According to still further features in the described preferred embodiments the optical device includes a threaded fiber optic array with a plurality of fibers with two ends.
According to still further features in the described preferred embodiments the reference insert includes a mirror on an upper surface of the reference insert, the mirror being adapted to establish the reference guideline.
According to still further features in the described preferred embodiments the plurality of fibers includes at least one transmitting fiber, with a light source connected to a first end of the two ends, and at least one receiving fiber, with a light receptor at a first end of the two ends.
According to still further features in the described preferred embodiments the at least one transmitting fiber and the at least one receiving fiber are adapted to establish the alignment axis such that a light beam transmitted from a second end of the at least one transmitting fiber incident upon the mirror and reflected by the mirror is received by the first end of the at least one receiving fiber of the optical device only when the alignment axis and the reference guideline are colinearly aligned.
According to still further features in the described preferred embodiments a display element is connected to a second end of the at least one receiving fiber of the optical device.
According to still further features in the described preferred embodiments the display element is selected from the group consisting of a lens on the second end of the at least one receiving fiber, a miniature screen, an optical display, a photosensitive cell and a light detector.
According to still further features in the described preferred embodiments the light detector is connected to a signaling device.
According to still further features in the described preferred embodiments the signaling device produces an audible signal.
According to still further features in the described preferred embodiments the system is used for drilling the hole in bone for a dental implant.
According to still further features in the described preferred embodiments the system is used for drilling the hole in bone for an orthopedic fixation appliance.
According to still further features in the described preferred embodiments the method is used for drilling the hole in bone for a dental implant.
According to still further features in the described preferred embodiments the method is used for drilling the hole in bone for an orthopedic fixation appliance.
The present invention successfully addresses the shortcomings of the presently known configurations by providing a system and method for the positioning and drilling of holes for the fixation of surgical implants and, more particularly, to an optical system and a method to assist a surgeon, and more particularly a dental implantologist or an orthopedic surgeon, in drilling at a predetermined location, distance and angulations relative to references. It is an object of the present invention to provide means for drilling and enlarging consecutive holes, at a predetermined distance to optimize the orientation of holes so as to support the implants without affecting the strength of the bone.
Still another object of the present invention is to provide an optical arrangement that enables alignment of drilling at a predetermined angle to an existing hole at a predetermined distance, by means of auto-collimation or by means of target alignments. A particular case is the drilling and enlarging the holes for the implants with their central axes parallel to each other, to assure optimal loading and minimal stress on the implants.
Still another object of this invention is to provide guidance for drilling according to a predetermined drilling plan.
Still another object of the present invention is to provide the above-mentioned feature without altering the drilling tools, methods and procedures in use today.
Still a further object is to guide drilling up to the full depth of the holes, and allowing use of the full range of sizes of drill bit, up to the final diameter.
A further object is to provide a time saving method for guidance of drilling of medical holes which presents no hazard to the patient, including, for example, avoiding the hazard of radiation exposure which is inherent in the use of x-ray localization for guidance in drilling positioning.